Norton was a jello jawed boxer who got rocked by every hard hitting opponent he ever faced. Shavers, Foreman blitzed this pretty boy with violent dispatch. Wlad would back this pretender up with his power left jab, hurt him badly with his quick follow up left hook and finish him with a straight right probably within two rounds. He did well against Ali because Ali was out of shape and did not possess knockout power, his really only weakness. But he was still the greatest, just not a power puncher like Wlad.
Norton would get annihilated by either brother. He had a fragile mandible and got laid out by almost every puncher he fought. This isn't to mention he is significantly below either brother's skill level or talent level.
The first jab Wlad lands would wobble Norton. He'd go straight into survival mode. Huge mismatch ending in a brutal KO.